scholarly journals Investigation of Atmospheric Rivers Impacting the Pigeon River Basin of the Southern Appalachian Mountains

2018 ◽  
Vol 33 (1) ◽  
pp. 283-299 ◽  
Author(s):  
Douglas K. Miller ◽  
David Hotz ◽  
Jessica Winton ◽  
Lukas Stewart
Keyword(s):  
North Carolina ◽  
River Basin ◽  
Large Scale ◽  
Large Fraction ◽  
Appalachian Mountains ◽  
Warm Season ◽  
Atmospheric Rivers ◽  
Southern Appalachian Mountains ◽  
Low Level ◽  
Southern Appalachian

Abstract Rainfall observations in the Pigeon River basin of the southern Appalachian Mountains over a 5-yr period (2009–14) are examined to investigate the synoptic patterns responsible for downstream flooding events as observed near Knoxville, Tennessee, and Asheville, North Carolina. The study is designed to address the hypothesis that atmospheric rivers (ARs) are primarily responsible for the highest accumulation periods observed by the gauge network and that these periods correspond to events having a societal hazard (flooding). The upper 2.5% (extreme) and middle 33% (normal) rainfall events flagged using the gauge network observations showed that half of the heaviest rainfall cases were associated with an AR. Of those extreme events having an AR influence, over 73% had a societal hazard defined as minor-to-major flooding at the USGS river gauge located in Newport, Tennessee, or flooding observations for locations near the Tennessee and North Carolina border reported in the Storm Data publication. Composites of extreme AR-influenced events revealed a synoptic pattern consisting of a highly amplified slow-moving positively tilted trough, suggestive of the anticyclonic Rossby wave breaking scenario that sometimes precedes hydrological events of high impact. Composites of extreme non-AR events indicated a large-scale weather pattern typical of a warm season scenario in which an anomalous low-level cyclone, cut off far from the primary upper-tropospheric jet, was located in the southeastern United States. AR events without a societal hazard represented a large fraction (75%–88%) of all ARs detected during the study period. Synoptic-scale weather patterns of these events were fast moving and had weak low-level atmospheric dynamics.

scholarly journals An Expanded Investigation of Atmospheric Rivers in the Southern Appalachian Mountains and Their Connection to Landslides

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 71 ◽  
Author(s):  
Douglas K. Miller ◽  
Chelcy Ford Miniat ◽  
Richard M. Wooten ◽  
Ana P. Barros
Keyword(s):  
North Carolina ◽  
River Basin ◽  
Appalachian Mountains ◽  
Extreme Rainfall ◽  
River Basins ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Southern Appalachian Mountains ◽  
Southern Appalachian ◽  
Western North Carolina

Previous examination of rain gauge observations over a five-year period at high elevations within a river basin of the southern Appalachian Mountains showed that half of the extreme (upper 2.5%) rainfall events were associated with an atmospheric river (AR). Of these extreme events having an AR association, over 73% were linked to a societal hazard at downstream locations in eastern Tennessee and western North Carolina. Our analysis in this study was expanded to investigate AR effects in the southern Appalachian Mountains on two river basins, located 60 km apart, and examine their influence on extreme rainfall, periods of elevated precipitation and landslide events over two time periods, the ‘recent’ and ‘distant’ past. Results showed that slightly more than half of the extreme rainfall events were directly attributable to an AR in both river basins. However, there was disagreement on individual ARs influencing extreme rainfall events in each basin, seemingly a reflection of its proximity to the Blue Ridge Escarpment and the localized terrain lining the river basin boundary. Days having at least one landslide occurring in western North Carolina were found to be correlated with long periods of elevated precipitation, which often also corresponded to the influence of ARs and extreme rainfall events.

scholarly journals A Study of Two Impactful Heavy Rainfall Events in the Southern Appalachian Mountains during Early 2020, Part I; Societal Impacts, Synoptic Overview, and Historical Context

2021 ◽  
Vol 13 (13) ◽  
pp. 2452
Author(s):  
Douglas Miller ◽  
John Forsythe ◽  
Sheldon Kusselson ◽  
William Straka III ◽  
Jifu Yin ◽  
...  
Keyword(s):  
Heavy Rainfall ◽  
Large Scale ◽  
Appalachian Mountains ◽  
Environmental Stability ◽  
Antecedent Soil Moisture ◽  
Rainfall Events ◽  
Southern Appalachian Mountains ◽  
Low Level ◽  
Southern Appalachian ◽  
Heavy Rainfall Events

Two heavy rainfall events occurring in early 2020 brought flooding, flash flooding, strong winds and tornadoes to the southern Appalachian Mountains. The atmospheric river-influenced events qualified as extreme (top 2.5%) rain events in the archives of two research-grade rain gauge networks located in two different river basins. The earlier event of 5–7 February 2020 was an event of longer duration that caused significant flooding in close proximity to the mountains and had the higher total accumulation observed by the two gauge networks, compared to the later event of 12–13 April 2020. However, its associated downstream flooding response and number of landslides (two) were muted compared to the April event (21). The purpose of this study is to understand differences in the surface response of the two events, primarily by examining the large-scale weather pattern and available space-based observations. Both storms were preceded by anticyclonic Rossby wave breaking events that led to a highly amplified 500 hPa wave during the February storm (a broad continent-wide 500 hPa cyclone during the April storm) in which the accompanying low-level cyclone moved slowly (rapidly). Model analyses and space-based water vapor observations of the two events indicated a deep sub-tropical moisture source during the February storm (converging sub-tropical low-level moisture streams and a dry mid-tropospheric layer during the April storm). Systematic differences of environmental stability were reflected in differences of storm-averaged rain rate intensity, with large-scale atmospheric structures favoring higher intensities during the April storm. Space-based observations of post-storm surface conditions suggested antecedent soil moisture conditioned by rainfall of the February event made the widespread triggering of landslides possible during the higher intensity rains of the April event, a period exceeding the 30 day lag explored in Miller et al. (2019).

scholarly journals Aerosol-precipitation interactions in the southern Appalachian Mountains

2012 ◽  
Vol 12 (2) ◽  
pp. 5487-5517 ◽  
Author(s):  
G. M. Kelly ◽  
B. F. Taubman ◽  
L. B. Perry ◽  
J. P. Sherman ◽  
P. T. Soulé ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Source Region ◽  
Appalachian Mountains ◽  
Warm Season ◽  
Synoptic Classification ◽  
Southern Appalachian Mountains ◽  
Aerosol Loading ◽  
Southern Appalachian ◽  
Aerosol Properties ◽  
Precipitation Events

Abstract. There are many uncertainties associated with aerosol-precipitation interactions, particularly in mountain regions where a variety of processes at different spatial scales influence precipitation patterns. Aerosol-precipitation linkages were examined in the southern Appalachian Mountains, guided by the following research questions: (1) how do aerosol properties observed during precipitation events vary by season (e.g., summer vs. winter) and synoptic event type (e.g., frontal vs. non-frontal); and (2) what influence does air mass source region have on aerosol properties? Precipitation events were identified based on regional precipitation data and classified using a synoptic classification scheme developed for this study. Hourly aerosol data were collected at the Appalachian Atmospheric Interdisciplinary Research (AppalAIR) facility at Appalachian State University in Boone, NC (1110 m a.s.l., 36.215°, −81.680°). Backward air trajectories provided information on upstream atmospheric characteristics and source regions. During the warm season (June to September), greater aerosol loading dominated by larger particles was observed, while cool season (November to April) precipitation events exhibited overall lower aerosol loading with an apparent influence from biomass burning particles. Aerosol-induced precipitation enhancement may have been detected in each season, particularly during warm season non-frontal precipitation.

scholarly journals Frequency of sprout-origin trees in pre-European settlement forests of the southern Appalachian Mountains

2016 ◽  
Vol 46 (8) ◽  
pp. 1019-1025 ◽  
Author(s):  
Carolyn A. Copenheaver ◽  
Tara L. Keyser
Keyword(s):  
Large Scale ◽  
Tree Mortality ◽  
Deciduous Forest ◽  
Appalachian Mountains ◽  
Acer Rubrum ◽  
Blue Ridge ◽  
Southern Appalachian Mountains ◽  
European Settlement ◽  
Southern Appalachian ◽  
Witness Trees

We hypothesized that tree form, recorded in historical public land surveys, would provide a valuable proxy record of regeneration patterns during early-European settlement of North America’s eastern deciduous forest. To test this hypothesis, we tallied stem form from witness trees used in land survey records in the southern Appalachian Mountains from 13 counties spanning four physiographic provinces: Piedmont, Blue Ridge, Ridge and Valley, and Cumberland Plateau. A total of 3% of witness trees used in the land surveys were of sprout origin. American basswood (Tilia americana L.) exhibited the highest proportion of sprout-origin trees at 12%. Other overstory species with a high proportion of sprout-origin trees were hickory (Carya sp.), red maple (Acer rubrum L.), and sycamore (Platanus occidentalis L.), all with 6% of stems being from sprout origin. Blue Ridge had significantly more sprout-origin trees compared with the other three physiographic provinces. Forests in the southern Appalachian Mountains during the pre-European settlement period had a suite of disturbances that controlled their growth and regeneration; however, most of these disturbances did not result in large-scale tree mortality, and therefore, sprouts were not an important source of regeneration.

Sign in / Sign up

Export Citation Format

Share Document